Various types of lawn mowers, including riding lawn mowers and push mowers, for example, are known in the art. Such mowers typically include a blade assembly having a rotary cutting blade, a mower engine which rotates the cutting blade, and wheels which facilitate transport of the mower. Mowers may also be equipped with a conduit and blower assembly for distributing clippings from the blade assembly to a hopper.
A conventional blade assembly for a lawn mower typically includes an elongated, flat rotary cutting blade the middle of which is mounted to a blade shaft. Each leading edge of the blade is tapered to cut grass. The weight of the blade is substantially evenly distributed along the entire length of the blade. Some blade assemblies may include two or more cutting blades.
As it is rotated on the blade shaft by the mower engine, the flat rotary cutting blade encounters resistance friction from three different sources. First, the blade encounters friction when it initially contacts and cuts the grass or other material being cut. Second, the flat bottom of the blade encounters the upper end of the grass or material which was just cut by the blade. Third, the blade encounters friction from air and cut grass fragments or material which swirls around inside the blade housing of the mower.
The conventional rotary cutting blade suffers from several drawbacks. First, when it encounters friction as described above, the blade loses inertia due to the even weight distribution along the entire length of the blade. This inhibits the cutting efficiency of the blade. Second, due to the shape of the blade, air flow resistance is inherently high. Third, the blade contacts grass at a 90 degree angle and on a 1:1 ratio (the blade typically cuts the grass once each time it contacts the grass), and also tends to smash and tear, rather than cut and slice, the grass.
There is therefore an established need for an improved cutting blade assembly which may be adapted for use in a lawnmower, blender, food processor or other application and which is characterized by substantially increased inertia and reduced friction imparted by a material as the material is cut, mulched, sliced, or blended.